EP2266851A1 - Braking force control device for vehicles - Google Patents

Braking force control device for vehicles Download PDF

Info

Publication number
EP2266851A1
EP2266851A1 EP09713889A EP09713889A EP2266851A1 EP 2266851 A1 EP2266851 A1 EP 2266851A1 EP 09713889 A EP09713889 A EP 09713889A EP 09713889 A EP09713889 A EP 09713889A EP 2266851 A1 EP2266851 A1 EP 2266851A1
Authority
EP
European Patent Office
Prior art keywords
braking force
braking
brake device
force
time
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09713889A
Other languages
German (de)
English (en)
French (fr)
Inventor
Takeshi Ishimoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nissan Motor Co Ltd
Original Assignee
Nissan Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Publication of EP2266851A1 publication Critical patent/EP2266851A1/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
    • B60T13/14—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using accumulators or reservoirs fed by pumps
    • B60T13/142—Systems with master cylinder
    • B60T13/147—In combination with distributor valve
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/48—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition connecting the brake actuator to an alternative or additional source of fluid pressure, e.g. traction control systems
    • B60T8/4809—Traction control, stability control, using both the wheel brakes and other automatic braking systems
    • B60T8/4827—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems
    • B60T8/4863—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems
    • B60T8/4872—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems pump-back systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T2201/00—Particular use of vehicle brake systems; Special systems using also the brakes; Special software modules within the brake system controller
    • B60T2201/02—Active or adaptive cruise control system; Distance control

Definitions

  • the present invention relates to the control of a hydraulic brake system in which a manual brake, actuated by a driver's operation, and an automatic brake, automatically actuated without driver's operation, are combined with each other.
  • a driver's brake-pedal depression occurring during operation of the automatic brake gives the driver an uncomfortable feeling that the brake pedal is undesirably forced to move down and thus drawn in, due to a less brake-pedal reaction force or an insufficient reaction force weakened as compared to a normal brake-pedal reaction force.
  • an automatic brake device configured to produce a brake fluid pressure by actuating an automatic brake means, when it is determined that a great deceleration is required to avoid a collision of a host vehicle with a preceding vehicle ahead of the host vehicle, or when it is determined that, when executing an automatic running mode while maintaining a vehicle-to-vehicle distance to the preceding vehicle at a given distance, the vehicle-to-vehicle distance becomes shorter than the given distance.
  • a transition from the automatic brake state to the manual brake state occurs.
  • the device is configured to open a cut-off valve when a master-cylinder pressure, produced by the driver's braking operation, and a wheel-cylinder pressure, obtained by the automatic brake, become approximately equal to each other, so as to avoid the occurrence of a poor brake feel that a feel of braking operation is temporarily reduced and an uncomfortable feeling such as a brake-pedal kickback.
  • Patent document 1 Japanese patent provisional publication No. JP8-198075 (A )
  • the automatic brake function becomes canceled or deactivated when a transition from the automatic brake state to the driver's manual brake state occurs.
  • the device has a problem as hereunder discussed. That is, according to the technology described in the patent document 1, when the braking force created by the driver's manual brake is less than the braking force created by the automatic brake during a transition from the automatic brake state to the manual brake state, a deceleration rate tends to reduce. This leads to the problem of the occurrence of a poor deceleration feel.
  • an object of the invention to provide a braking force control device having a high deceleration control responsiveness and configured to avoid a poor deceleration feel that can be caused during a mode shift from an automatic brake mode to a manual brake mode and also to avoid an uncomfortable brake-pedal drawn-in feeling that can be caused during a mode shift from a manual brake mode to an automatic brake mode.
  • a braking force control device for vehicles comprising a manual brake device, an automatic brake device, and a controller, the controller comprising an automatic-brake selective-actuation section configured to compare a braking force created by the manual brake device with a required braking force for the automatic brake device and to selectively actuate the automatic brake device when the required braking force exceeds in braking-force magnitude, a braking-force-difference time-rate-of-change calculation section configured to calculate a braking-force-difference time rate of change corresponding to a rate of change per unit time in a difference, which difference is obtained by subtracting the required braking force for the automatic brake device from the braking force created by the manual brake device, and a required braking force control section configured to correct the required braking force for the automatic brake device in a manner so as to reduce the required braking force when selectively actuating the automatic brake device and to correct a reducing amount of the required braking force in
  • the automatic brake device of the invention a comparison between a braking force created by a manual brake device and a required braking force for an automatic brake device is made, and then the automatic brake device is selectively actuated when the required braking force exceeds in braking-force magnitude. That is, it is possible to selectively execute a brake mode having a higher one of the braking force created by the manual brake device and the required braking force for the automatic brake device. Therefore, even when the braking force created by the driver's manual brake is less than the braking force for the automatic brake, the automatic brake device comes into operation so as to achieve the required braking force, thus eliminating a poor deceleration feel.
  • the time rate of change in the braking force difference is great, a reducing amount of the required braking force for the automatic brake device can be reduced.
  • a more quick braking action by greatly enhancing the braking force created by the automatic brake device rather than the braking force created by the manual brake device, and also to alleviate an uncomfortable brake-pedal drawn-in feeling.
  • the time rate of change in the braking force difference is small, the reducing amount of the required braking force for the automatic brake device can be increased.
  • the braking force control device of the invention on an automotive vehicle whose automatic brake device is equipped with an intelligent transport system (ITS), it is possible to prevent a collision with the preceding vehicle by generating a deceleration greater than the magnitude of braking force created by the driver's manual brake by virtue of the automatic brake device, and also to maintain a vehicle-to-vehicle distance between the preceding vehicle and the host vehicle at a predetermined distance.
  • ITS intelligent transport system
  • Fig. 1 is a block diagram illustrating a total system configuration of one embodiment of a braking force control device made according to the invention, the braking force control device connected to a hydraulic brake system and including a controller and various sensors.
  • a running-control controller 101 configured to control an acceleration/deceleration of a vehicle
  • an ITS-control controller 102 configured to calculate target running indexes (e.g., a target acceleration/deceleration and a target vehicle speed and the like) suited to an optimal road traffic, are constructed by a microcomputer, so as to execute a running-control process based on detected signals from various sensors, and to automatically accelerate or decelerate the vehicle depending on a vehicle running state by controlling operations of an engine-output control unit 111 and a braking-force control unit 112.
  • an optical non-contact steering angle sensor 107 for detecting a steering angle ⁇ of a steering wheel
  • a lateral-G and yaw-rate sensor 108 for detecting a lateral gravity and yaw rate of the vehicle
  • a master-cylinder pressure sensor 109 for
  • the ITS-control controller 102 receives signals from a white-lane-mark recognition means 103 such as a camera for recognizing a white line of a lane, a road-environment recognition means 104 such as a navigator for recognizing a road environment, and an object recognition means 105 such as a laser radar for recognizing a preceding vehicle or a frontally-located object ahead of the host vehicle. In this manner, a running environment and a running state of the host vehicle are read.
  • a white-lane-mark recognition means 103 such as a camera for recognizing a white line of a lane
  • a road-environment recognition means 104 such as a navigator for recognizing a road environment
  • an object recognition means 105 such as a laser radar for recognizing a preceding vehicle or a frontally-located object ahead of the host vehicle.
  • Fig. 2 is a schematic diagram illustrating the configuration of the braking-force control device.
  • braking force control unit 112 is interleaved between a master cylinder 3 and each of wheel cylinders 11FL, 11FR, 11RL, and 11RR.
  • Master cylinder 3 is a tandem master cylinder in which dual-brake-system fluid pressures are produced depending on a leg-power on the pedal, input from a brake pedal 1 depressed and operated by a driver's foot and multiplied by a working-fluid-pressure booster 2.
  • Master cylinder 3 is equipped with a reservoir 4 for storing hydraulic brake fluid under atmospheric pressure, and for supplying hydraulic brake fluid from reservoir 4 to master cylinder 3.
  • Braking-force control unit 112 adopts an X-split diagonal layout of brake circuits.
  • the primary side P of master cylinder 3 is connected to front-left and rear-right wheel cylinders 11FL and 11RR.
  • the secondary side S of master cylinder 3 is connected to front-right and rear-left wheel cylinders 11FR and 11RL.
  • Each of wheel cylinders 11FL ⁇ 11RR is built in a disc brake in which a disk rotor can be sandwiched by brake pads under contact pressure to produce a braking force or a drum brake in which a brake shoe can be pushed against an inner peripheral surface of a brake drum to produce a braking force.
  • Braking-force control unit 112 utilizes a hydraulic brake pressure control circuit, for use in an anti-skid braking system (ABS), a traction control system (TCS), a stability control or a vehicle dynamics control system (VDC), and the like.
  • the braking-force control unit is configured to pressure-increase, hold, or decrease a fluid pressure in each individual wheel cylinder 11FL ⁇ 11RR, regardless of the presence or absence of a driver's braking operation.
  • the brake circuit of the primary side P connected to master cylinder 3 via a fluid-pressure line 6, is equipped with a normally-open first gate valve 12A capable of closing a fluid passage between master cylinder 3 and wheel cylinder 11FL (11RR), a normally-open inlet valve 13FL (13RR) capable of closing a fluid passage between first gate valve 12A and wheel cylinder 11FL (11RR), an accumulator 14 communicating with a fluid passage between wheel cylinder 11FL (11RR) and inlet valve 13FL (13RR), a normally-closed outlet valve 15FL (15RR) capable of opening a fluid passage between wheel cylinder 11FL (11RR) and accumulator 14, a normally-open second gate valve 16A capable of opening a communication passage intercommunicating a fluid passage between master cylinder 3 and first gate valve 12A and a fluid passage between accumulator 14 and outlet valve 15FL (15RR), and a pump-and-motor unit 17 whose suction side is communicated with the fluid passage between accumulator 14 and outlet valve 15FL (15RR) and whose discharge side
  • first gate valve 12B an inlet valve 13FR (13RL), an accumulator 14, an outlet valve 15FR (15RL), a second gate valve 16B, pump-and-motor unit 17, and a damper chamber 18.
  • first gate valves 12A, 12B, inlet valves 13FL ⁇ 13RR, outlet valves 15FL ⁇ 15RR, and second gate valves 16A, 16B is constructed by a two-port two-position switching, single solenoid, spring-offset electromagnetic-solenoid-operated valve.
  • First gate valves 12A, 12H and inlet valves 13FL ⁇ 13RR are configured to open their fluid passages at their de-energized normal positions, whereas outlet valves 15FL ⁇ 15RR, and second gate valves 16A, 16B are configured to close their fluid passages at their de-energized normal positions.
  • Accumulator 14 is a spring-type accumulator in which a piston in a cylinder is preloaded with a compression spring at a side of the piston facing the spring end.
  • Pump-and-motor unit 17 is comprised of a displacement type pump, such as a gear pump or a piston pump, capable of assuring an approximately constant discharge regardless of load/pressure, and a DC motor.
  • a displacement type pump such as a gear pump or a piston pump, capable of assuring an approximately constant discharge regardless of load/pressure, and a DC motor.
  • inlet valve 13FL (13RR) is energized and closed with first gate valve 12A, outlet valve 15FL (15RR), and second gate valve 16A all kept at their de-energized normal positions, the fluid passage from wheel cylinder 11FL (11RR) to master cylinder 3 and accumulator 14 is blocked, so as to hold the fluid pressure in wheel cylinder 11FL (11RR) (an automatic-brake pressure fold mode).
  • the operation of a usual manual brake and the operation of an automatic brake by which a selected one of a fluid pressure increase, a fluid pressure hold, and a fluid pressure decrease is executable are similar to those of the primary side P, and thus detailed description of the operations of the secondary side will be omitted because the above description thereon seems to be self-explanatory.
  • running-control controller 101 is configured to increase, hold, or decrease the respective wheel cylinders 11FL ⁇ 11RR by controlling operations of first gate valve 12A ⁇ 12B, inlet valves 13FL ⁇ 13RR, outlet valves 15FL ⁇ 15RR, second gate valve 16A ⁇ 16B, and pump-and-motor 17. That is, running-control controller 101 constructs an automatic brake means which is configured to obtain a fluid pressure from pump 17, and also to control braking forces of the road wheels based on a running environment and a running state of the host vehicle.
  • the shown embodiment adopts an X-split diagonal layout in which the hydraulic brake system is divided into brake circuits respectively associated with front-left and rear-right wheel cylinders 11FL ⁇ 11RR and front-right and rear-left wheel cylinders 11FR ⁇ 11RL. It will be appreciated that the invention is not limited to the particular embodiments shown and described herein, but that the concept of the invention may be applied to a front-and-rear parallel layout of brake circuits in which the hydraulic brake system is divided into brake circuits respectively associated with front-left and front-right wheel cylinders 11FL ⁇ 11FR and rear-left and rear-right wheel cylinders 11RL ⁇ 11RR.
  • the shown embodiment adopts a spring-type accumulator 14.
  • the invention is not limited to the particular embodiments shown and described herein, but that the concept of the invention may be applied to any type of accumulators, such as a gas-compression straight-hydraulic type, a piston-type, a metal-bellows type, or a diaphragm type, by which hydraulic brake fluid relieved from the wheel cylinders 11FL ⁇ 11RR can be temporarily stored and the wheel cylinder pressure decrease can be efficiently performed.
  • the shown embodiment adopts a hydraulic system, which is configured so that a fluid passage is opened with first gate valve 12A ⁇ 12B and inlet valves 13FL ⁇ 13RR all kept at their de-energized normal positions, and that the fluid passage is closed with outlet valves 15FL ⁇ 15RR and second gate valve 16A ⁇ 16B all kept at their de-energized normal positions.
  • a hydraulic system which is configured so that a fluid passage is opened with first gate valve 12A ⁇ 12B and inlet valves 13FL ⁇ 13RR all kept at their de-energized normal positions, and that the fluid passage is closed with outlet valves 15FL ⁇ 15RR and second gate valve 16A ⁇ 16B all kept at their de-energized normal positions.
  • the invention may be applied to a system configuration in which a fluid passage is opened with first gate valve 12A ⁇ 12B and inlet valves 13FL ⁇ 13RR all kept at their energized offset positions, and the fluid passage is closed with outlet valves 15FL ⁇ 15RR and second gate valve 16A ⁇ 16B all kept at their energized offset positions.
  • the control routine executed by running-control controller 101, is hereunder described in detail in reference to the flowchart of Fig. 3 .
  • the control routine is executed as time-triggered interrupt routines to be triggered every predetermined time intervals such as 10 milliseconds.
  • step S2 in order to realize the target running indexes determined based on a running environment and a running state of the host vehicle, data calculated by ITS-control controller 102 (that is, an ITS-control required value mc_ITS and an ITS-control required flag, both of which correspond to an ITS fluid-pressure required value), are read.
  • ITS-control controller 102 that is, an ITS-control required value mc_ITS and an ITS-control required flag, both of which correspond to an ITS fluid-pressure required value
  • step S3 in order to determine whether or not the manual brake is actuated by the driver, a check is made to determine whether the brake switch is turned ON.
  • step S3 determines that the brake switch is turned ON, the routine proceeds to step S4.
  • step S4 a check is made to determine whether master-cylinder pressure mc_P is greater than or equal to a predetermined pressure mc_P_min.
  • the predetermined pressure mc_P_min may be set to a pressure level at which a clearance existing between the brake pad and the brake caliper becomes a zero clearance, (that is, at which a non-effective to effective transition of the fluid pressure occurs).
  • the predetermined pressure may be set to a hydraulic brake pressure (e.g., 2kgf/cm 2 ), which is determined, fully taking into account each sensor's operating characteristics of master-cylinder pressure sensor 109. By using or detecting both sensor signals from brake switch 110 and master-cylinder pressure sensor 109, a redundant system would result for enhanced reliability purposes of braking force control.
  • step S4 determines that master-cylinder pressure mc_P is greater than or equal to the predetermined pressure mc_P_min
  • the routine proceeds to step S5.
  • step S5 a check is made to determine whether a braking-force requirement from ITS-control controller 102 is present or absent.
  • step S5 determines that the braking-force requirement is absent, the current execution cycle of the control routine terminates, and thus braking-force control unit 112 operates to brake the road wheels by the usual manual brake means.
  • step S6 in a manner so as to selectively actuate the automatic brake device in response to a target fluid pressure Pm (described later) determined based on ITS-control required value mc_ITS and master-cylinder pressure mc_P, control actions for pump-and-motor unit 17 and respective valves 12, 13, 15, and 16 are executed.
  • Pm target fluid pressure
  • target fluid pressure Pm required for execution of deceleration control
  • a front-wheel target braking force Fm_f and a rear-wheel target braking force Fm_r are calculated based on the target fluid pressure Pm calculated as discussed above, as follows.
  • step S6 corresponds to the automatic-brake selective-actuation section.
  • step S6 generally, when the automatic brake comes into operation during operation of the driver's manual brake, the pump motor starts to rotate and thus hydraulic brake fluid is drawn from the master-cylinder side. Hence, there is a problem that a brake-pedal drawn-in phenomenon occurs.
  • an automatic brake comes into operation during braking of the road wheels by a driver's manual-brake operation and then a braking force created by the automatic brake exceeds a braking force created by the driver's manual brake (i.e., a pressure-increasing side of the automatic brake).
  • a braking force created by the automatic brake exceeds a braking force created by the driver's manual brake (i.e., a pressure-increasing side of the automatic brake).
  • braking-force control unit 112 is constructed by a hydraulic-brake actuator equipped with pump-and-motor unit 17, and thus pump-and-motor unit 17 is rotated during operation of the automatic brake in such a manner as to draw hydraulic brake fluid from the side of master cylinder 3 and to force-feed the discharged hydraulic brake fluid to the side of wheel cylinder 11, and thus a braking force is produced.
  • pump-and-motor unit 17 is rotated during operation of the automatic brake in such a manner as to draw hydraulic brake fluid from the side of master cylinder 3 and to force-feed the discharged hydraulic brake fluid to the side of wheel cylinder 11, and thus a braking force is produced.
  • a brake-pedal drawn-in phenomenon tends to occur in conjunction with a flow of hydraulic brake fluid drawn from the aide of master cylinder 3 into pump-and-motor unit 17, thus giving the driver an uncomfortable brake-pedal feel.
  • the motor speed of motor 17 is set to a relatively lower value as compared to a necessary actuation of the automatic brake executed at step S8 (described later), and whereby it is possible to reduce a brake-pedal drawn-in phenomenon.
  • the hydraulic brake pressure in the wheel cylinder becomes higher as compared to the absence of the manual brake, and thus it is possible to ensure an acceptable control responsiveness even when the motor speed is set to a lower value, thus suppressing an unnecessary motor-speed rise, and thereby suppressing a brush wear and a deteriorated pump-seal life, and also improving deteriorated noise/vibration properties, which may occur due to high-speed setting of the motor.
  • the fluid pressure in master cylinder 3 becomes higher, as compared to an inoperative state of the manual brake, and thus it is possible to ensure an acceptable control responsiveness even when the motor speed is set to a lower value, thus suppressing an unnecessary motor-speed rise, and thereby suppressing a brush wear of pump-and-motor unit 17 and a deteriorated pump-seal life, and also improving deteriorated noise/vibration properties, which may occur due to high-speed setting of the motor.
  • ITS-control required value mc_ITS becomes less than master-cylinder pressure mc_P after ITS-control required value mc_ITS has exceeded master-cylinder pressure mc_P (i.e., a pressure-decreasing side of the automatic brake).
  • a motor speed ⁇ _rpm is set to a higher value, as master-cylinder pressure mc_P increases.
  • Motor speed ⁇ _rpm can be selected between a minimum motor speed ⁇ _min and a maximum motor speed ⁇ _max, depending on mater-cylinder pressure mc_P (i.e., a_min ⁇ _rpm ⁇ _max).
  • the motor speed is determined continuously depending on a change in mater-cylinder pressure mc_P.
  • two-stage or three-stage motor speed maps may be used and preprogrammed depending on master-cylinder pressure mc_P, so that the motor speed can be determined by properly switching the preprogrammed motor speed maps depending on the master-cylinder pressure.
  • a motor-speed coefficient ⁇ ' is set to a higher value, as a time-rate-of-increase dmc_P/dt in master-cylinder pressure mc_P increases, on the assumption that a direction for depressing the brake pedal is positive.
  • the motor speed is obtained by multiplying motor-speed coefficient ⁇ '.
  • motor-speed coefficient ⁇ ' may be set within a speed range from 0 rpm to 2000 rpm, and motor-speed coefficient ⁇ ' may be determined, depending on a time-rate-of-increase dmc_P/dt in master-cylinder pressure mc_P, from a preprogrammed dmc_P/dt- ⁇ ' map, and then motor speed ⁇ _rpm may be calculated from the following formula.
  • ⁇ _rpm ⁇ _rpm ⁇ ⁇ 0 rpm ⁇ ⁇ ⁇ 2000 rpm
  • several previous values of time-rate-of-increase dmc_P/dt may be sampled and the sampled previous values may be subjected to equalization processing, and then motor-speed coefficient ⁇ ' may be determined, based on the equalized time-rate-of-increase dmc_P/dt, from a preprogrammed equalized time-rate-of-increase dmc_P/dt versus motor-speed coefficient ⁇ ' map, and then motor speed ⁇ _rpm may be calculated based on the determined motor-speed coefficient.
  • step S6 when operating pump-and-motor unit 17 and respective valves 12, 13, 15, and 16 at step S6, the detailed procedure regarding which timing these fluid-pressure control devices should come into operation at, is hereunder described in reference to the flowchart of Fig. 7 .
  • a time rate of change d ⁇ P/dt in the above-mentioned difference ⁇ P is calculated. Instead of using the current value of time rate of change d ⁇ P/dt, several previous values of time rate of change d ⁇ P/dt may be sampled and the equalization-processed time rate of change may be calculated and used.
  • step S13 the difference ⁇ P, calculated at the point of time when a transition of an ITS-control required flag to an ON state first occurs, is set to a reference value ⁇ P_flag. Then, the routine proceeds to step S14.
  • a threshold value ⁇ P_thr is determined based on the time rate of change d ⁇ P/dt, calculated through step S12 from a reference characteristic diagram indicated within step S14 of Fig. 7 .
  • the exemplified characteristic diagram is preprogrammed so that threshold value ⁇ P_thr, required for determining actuation timing of pump-and-motor unit 17 and second gate valve 16A ⁇ 16B, increases, as time rate of change d ⁇ P/dt increases.
  • step S15 reference value ⁇ P_flag, calculated at step S13 is compared to threshold value ⁇ P_thr, calculated at step S14, and then a check is made to determine whether the calculated threshold value is greater than or equal to the calculated reference value.
  • ⁇ P_thr ⁇ P_flag the routine proceeds to step S16.
  • step S16 control actions for pump-and-motor unit 17 and respective valves 12, 13, 15, and 16 are executed.
  • step S15 determines that the calculated threshold value is less than the calculated reference value, that is, ⁇ P_thr ⁇ P_flag, the routine proceeds to step S17.
  • step S17 a check is made to determine whether the calculated threshold value is greater than or equal to the calculated difference.
  • the routine proceeds to step S16, so as to execute control actions for pump-and-motor unit 17 and respective valves 12, 13, 15, and 16.
  • ⁇ P_thr ⁇ P the current execution cycle of the control routine terminates without executing control actions for pump-and-motor unit 17 and respective valves 12, 13, 15, and 16.
  • the threshold value ⁇ P_thr required for determining actuation timing, also becomes small (see step S14 of Fig. 7 ).
  • the flow defined by S11 ⁇ S12 ⁇ S13 ⁇ S14 ⁇ S15 ⁇ S17 ⁇ S11 is repeatedly executed.
  • pump-and-motor unit 17 and second gate valve 16A ⁇ 16B do not operate until a point of time nearer to the time when ITS-control required value mc_ITS begins to exceed master-cylinder pressure mc_P.
  • step S16 corresponds to a required braking force control means.
  • step S7 a check is made to determine whether a braking-force requirement from ITS-control controller 102 is present or absent.
  • step S8 determines that the braking-force requirement is present, the routine proceeds to step S8, so as to necessarily actuate the automatic brake device. That is, at step S8, in response to ITS-control required value mc_ITS, control actions for pump-and-motor unit 17 and respective valves 12, 13, 15, and 16 are executed. In this manner, the current execution cycle of the control routine terminates.
  • Time charts illustrated in Fig. 8 show variations in master-cylinder pressure mc_P, ITS-control required value mc_ITS, a signal from brake switch 110, a state of the ITS-control required flag, and operations of pump-and-motor unit 17 and second gate valve 16. For instance, assume that the brake switch is turned ON at the time t1, and master-cylinder pressure mc_P is outputted after the time t1, and then master-cylinder pressure mc_P is fixed to a constant pressure value.
  • ITS-control required value mc_ITS exceeds mater-cylinder pressure mc_P. After this, ITS-control required value mc_ITS reaches a maximum value and then begins to decrease. Thereafter, ITS-control required value mc_ITS becomes less than mater-cylinder pressure mc_P from the time t4. Then, ITS-control required value mc_ITS becomes "0" at the time t5.
  • target fluid pressure Pm can be indicated as a compound curve obtained by combining higher thick-line sections of two different thick lines indicating the two fluid-pressure characteristics indicated in the uppermost time chart of Fig. 8 .
  • Pump-and-motor unit 17 becomes activated (ON) and second gate valve 16 becomes activated (ON) at a certain point of time existing within a time interval between the time t2 and the time t3, during which interval ITS-control required value mc_ITS is increasing from "0", so as to prepare for automatic-brake selective actuation executed after the time t3.
  • the actuation timing of the fluid-pressure control devices of the automatic brake tends to vary as indicated by the arrows in Fig. 8 .
  • the detailed actuation-timing decision rule regarding which timing within the time interval between the time t2 and the time t3 pump-and-motor unit 17 and second gate valve 16 should come into operation at, is based on the previously-discussed flowchart of Fig. 7 .
  • the point of time t3 when ITS-control required value mc_ITS exceeds master-cylinder pressure mc_P serves as a basing point
  • the automatic brake control system is configured to operate pump-and-motor unit 17 and second gate valve 16A ⁇ 16B from a certain time before the basing point.
  • the point of time t2 when the ITS-control required flag becomes shifted to an ON state may serve as a basing point.
  • the automatic brake control system may be configured so that actuation timing is delayed, as a time rate of change d ⁇ P/dt in the above-mentioned difference ⁇ P decreases.
  • pump-and-motor unit 17 becomes deactivated (OFF) and simultaneously second gate valve 16 becomes deactivated (OFF).
  • the braking-force control device of the present embodiment employs a manual brake device configured to be connected to braking-force control unit 112 serving as a hydraulic brake system by which braking forces are applied to road wheels and also configured to brake the road wheels in response to master-cylinder pressure mc_P created with brake pedal 1 depressed and operated by a driver's foot, and an automatic brake device configured to obtain a fluid pressure from pump 17, and also to control braking forces applied to the road wheels based on ITS-control required value mc_ITS calculated by ITS-control controller 102 by which controller a running environment and a running state of the host vehicle are read in.
  • a manual brake device configured to be connected to braking-force control unit 112 serving as a hydraulic brake system by which braking forces are applied to road wheels and also configured to brake the road wheels in response to master-cylinder pressure mc_P created with brake pedal 1 depressed and operated by a driver's foot
  • an automatic brake device configured to obtain a fluid pressure from pump 17, and also to control braking forces applied to the
  • master-cylinder pressure mc_P created by the manual brake device
  • ITS-control required value mc_ITS inputted into the automatic brake device
  • master-cylinder pressure mc_P created by the manual brake device
  • ITS-control required value mc_ITS inputted into the automatic brake device
  • Fig. 9 is a flowchart illustrating a control routine further executed by running-control controller 101 of the embodiment.
  • the control routine is executed as time-triggered interrupt routines to be triggered every predetermined time intervals such as 10 milliseconds.
  • a vehicle speed V of a host vehicle is read in from wheel speed sensors 106, whereas a distance L from the host vehicle to a preceding vehicle and a velocity V0 of the preceding vehicle are read in from ITS-control controller 102.
  • ITS-control controller 102 is configured to recognize the preceding vehicle by a signal from object recognition means 105, and to measure the relative distance L from the host vehicle to the preceding vehicle, and further configured to calculate a velocity V0 of the preceding vehicle based on a time rate of change dL/dt in the relative distance L and the host vehicle speed V.
  • braking force F_d created by the manual brake is kept constant, and thus the time rate of change d ⁇ F/dt in the braking-force difference can be regarded as a gradient of the tangent of the curve representing a change in required braking force F_ITS. Therefore, step S22 corresponds to a time-to-collision calculation means, whereas step S23 corresponds to a braking-force-difference time-rate-of-change calculation means.
  • step S24 corresponds to a basic braking force calculation means.
  • step S26 collisionless braking force F_cc and required braking force F_ITS for the automatic brake are compared to each other.
  • collisionless braking force F_cc exceeds in braking-force magnitude (i.e., F_cc>F_ITS)
  • a second braking-force coefficient ⁇ is calculated and derived from the time rate of change d ⁇ F/dt in the braking-force difference, calculated at step S23, in reference to the relational diagram shown in Fig. 11 .
  • a second braking-force coefficient ⁇ is calculated and derived from the time rate of change d ⁇ F/dt in the braking-force difference, calculated at step S23, in reference to the relational diagram shown in Fig. 11 .
  • several previous values of time-rate-of-change d ⁇ F/dt may be sampled and the sampled previous values may be subjected to equalization processing, and then the second braking-force coefficient may be calculated, based on the equalized time-rate-of-change.
  • the second braking-force coefficient ⁇ increases from a minimum value ⁇ _min, as the time-rate-of-change d ⁇ F/dt increases, and then reaches "1" at a maximum (i.e., ⁇ 1).
  • the reducing amount of required braking force F_ITS for the automatic brake can be increased, and whereby it is possible to reasonably enhance the braking force created by the automatic brake rather than the braking force created by the manual brake, and also to more greatly alleviate an uncomfortable brake-pedal drawn-in feeling.
  • a third braking-force coefficient ⁇ ' is calculated and derived from an absolute value (
  • the third braking-force coefficient ⁇ ' increases from "1", as the absolute value

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Regulating Braking Force (AREA)
EP09713889A 2008-02-28 2009-02-25 Braking force control device for vehicles Withdrawn EP2266851A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2008048491 2008-02-28
JP2008331370A JP5228209B2 (ja) 2008-02-28 2008-12-25 車両の制動力制御装置
PCT/JP2009/053413 WO2009107663A1 (ja) 2008-02-28 2009-02-25 車両の制動力制御装置

Publications (1)

Publication Number Publication Date
EP2266851A1 true EP2266851A1 (en) 2010-12-29

Family

ID=41016050

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09713889A Withdrawn EP2266851A1 (en) 2008-02-28 2009-02-25 Braking force control device for vehicles

Country Status (5)

Country Link
US (1) US8346453B2 (zh)
EP (1) EP2266851A1 (zh)
JP (1) JP5228209B2 (zh)
CN (1) CN101932484B (zh)
WO (1) WO2009107663A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015030263A1 (en) * 2013-08-30 2015-03-05 Toyota Jidosha Kabushiki Kaisha Brake control device
WO2015194680A1 (en) * 2014-06-17 2015-12-23 Toyota Jidosha Kabushiki Kaisha Brake control device

Families Citing this family (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4712833B2 (ja) * 2008-06-25 2011-06-29 日立オートモティブシステムズ株式会社 ブレーキ制御装置およびその制御方法
US9233673B2 (en) * 2009-04-14 2016-01-12 Honda Motor Co., Ltd. BBW brake device
JP5680325B2 (ja) * 2010-03-30 2015-03-04 富士重工業株式会社 車両の路外逸脱防止制御装置
EP2860076A4 (en) * 2012-06-04 2016-07-20 Hino Motors Ltd AUTOMATIC BRAKE CONTROL DEVICE
JP6000663B2 (ja) * 2012-06-04 2016-10-05 日野自動車株式会社 自動制動制御装置
JP6000662B2 (ja) * 2012-06-04 2016-10-05 日野自動車株式会社 自動制動制御装置
US9096199B2 (en) * 2013-10-09 2015-08-04 Ford Global Technologies, Llc Monitoring autonomous vehicle braking
JP6379510B2 (ja) * 2014-02-18 2018-08-29 日産自動車株式会社 運転診断装置および保険料算定方法
KR101603262B1 (ko) * 2014-11-04 2016-03-14 주식회사 만도 차량용 제동 제어 장치 및 그 제동 제어 방법
JP6543078B2 (ja) * 2015-04-27 2019-07-10 本田技研工業株式会社 車両用ブレーキ装置
US10167015B2 (en) * 2015-05-11 2019-01-01 GM Global Technology Operations LLC System for retrofitting vehicle automation
KR101657075B1 (ko) * 2015-07-10 2016-09-13 한국기계연구원 스마트 제동시스템
DE102016209042A1 (de) * 2016-05-24 2017-11-30 Robert Bosch Gmbh Verfahren zum Überwachen der Bremskraft in einem Fahrzeug
DE102017004885A1 (de) * 2017-05-20 2018-11-22 Wabco Gmbh Verfahren zur Schätzung der erreichbaren Gesamtbremskräfte zur automatisierten Verzögerung eines Nutzfahrzeugs, Bremsanlage sowie Nutzfahrzeug damit
CN107310543A (zh) * 2017-07-01 2017-11-03 南京珑瑞柯创汽车科技有限公司 一种新型电磁式汽车钳盘制动***
DE102018205520A1 (de) * 2018-04-12 2019-10-17 Robert Bosch Gmbh Bremssystem für ein zweiachsiges Fahrzeug und Verfahren zum Betreiben eines Bremssystems eines zweiachsigen Fahrzeugs
JP7031498B2 (ja) * 2018-05-30 2022-03-08 トヨタ自動車株式会社 運転支援装置
US10940884B2 (en) * 2018-06-08 2021-03-09 GM Global Technology Operations LLC Systems and methods for brake pull mitigation
TWI687329B (zh) * 2018-12-19 2020-03-11 宏碁股份有限公司 剎車控制方法、剎車系統及車輛
EP3983277A1 (en) * 2019-06-11 2022-04-20 Volvo Truck Corporation A method for estimating a longitudinal force difference acting on steered wheels
KR102668167B1 (ko) * 2019-08-02 2024-05-29 에이치엘만도 주식회사 차량의 제어 장치, 그 제어 방법 및 차량 제어 시스템.
JP7303153B2 (ja) * 2020-05-18 2023-07-04 トヨタ自動車株式会社 車両用運転支援装置

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08198075A (ja) 1995-01-30 1996-08-06 Mazda Motor Corp 車両の自動ブレーキ装置
JP3890696B2 (ja) * 1997-09-24 2007-03-07 トヨタ自動車株式会社 自動ブレーキ装置
JP3651289B2 (ja) * 1998-12-03 2005-05-25 トヨタ自動車株式会社 ブレーキ制御装置
JP4332962B2 (ja) * 1999-12-13 2009-09-16 トヨタ自動車株式会社 車両用ブレーキシステム
CN1295952A (zh) * 2000-11-03 2001-05-23 华南理工大学 汽车防抱制动***参考车速确定方法及其制动控制程序
JP4345339B2 (ja) * 2003-04-09 2009-10-14 株式会社デンソー 制動制御装置
JP4415617B2 (ja) 2003-09-11 2010-02-17 株式会社アドヴィックス ブレーキ制御装置
JP2005306320A (ja) * 2004-04-26 2005-11-04 Mitsubishi Motors Corp 制動制御装置
JP4127245B2 (ja) * 2004-06-07 2008-07-30 日産自動車株式会社 車両用制動力制御装置
JP2006044590A (ja) * 2004-08-06 2006-02-16 Toyota Motor Corp 車両の減速制御装置
JP4887975B2 (ja) * 2005-12-08 2012-02-29 日産自動車株式会社 車両用ブレーキ装置
JP5024515B2 (ja) * 2006-06-28 2012-09-12 株式会社アドヴィックス 車両のブレーキ液圧制御装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2009107663A1 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015030263A1 (en) * 2013-08-30 2015-03-05 Toyota Jidosha Kabushiki Kaisha Brake control device
US9707943B2 (en) 2013-08-30 2017-07-18 Toyota Jidosha Kabushiki Kaisha Brake control device
WO2015194680A1 (en) * 2014-06-17 2015-12-23 Toyota Jidosha Kabushiki Kaisha Brake control device
CN106660529A (zh) * 2014-06-17 2017-05-10 丰田自动车株式会社 制动控制装置
CN106660529B (zh) * 2014-06-17 2019-03-19 丰田自动车株式会社 制动控制装置

Also Published As

Publication number Publication date
US8346453B2 (en) 2013-01-01
JP2009227266A (ja) 2009-10-08
US20110004385A1 (en) 2011-01-06
WO2009107663A1 (ja) 2009-09-03
CN101932484B (zh) 2013-05-15
CN101932484A (zh) 2010-12-29
JP5228209B2 (ja) 2013-07-03

Similar Documents

Publication Publication Date Title
US8346453B2 (en) Braking force control device for vehicles that corrects a reducing amount of required braking force
CA2193924C (en) Brake control apparatus for a vehicle
US8366210B2 (en) Braking apparatus for vehicle
US9061672B2 (en) Vehicle brake device and method of controlling vehicle brake device
US6007163A (en) Brake control apparatus for a vehicle
US20060122760A1 (en) Abs control system
EP2626261B1 (en) Electric vehicle brake control device
JP2002356156A (ja) 車輌用制動制御装置
JPH06206532A (ja) スキッドコントロール装置を有する液圧式自動車ブレーキ装置
JP3528415B2 (ja) 制動圧力制御装置
CN109941247B (zh) 车辆用制动力控制装置
EP0980803B1 (en) Braking force controller
US6338017B1 (en) Brake force distribution control device for automotive vehicles
JP5125944B2 (ja) ブレーキ制御装置
US6246946B1 (en) Automotive brake control system with skid control unit
JP4479593B2 (ja) 車両用ブレーキ装置
US6019439A (en) Method of operating an anti-locking automotive vehicle-brake system
JP5245564B2 (ja) 車両の制動力制御装置
JP2019069756A (ja) 車両用制動力制御装置
JP4419746B2 (ja) ブレーキ液圧制御装置
US5971502A (en) Secondary braking control
JP4677977B2 (ja) 制動速度に応じて制動力前後輪間配分比が制御される車輌用制動装置
JP2756507B2 (ja) 車両のトラクション制御方法
KR102656039B1 (ko) 전자 슬립 제어식 파워 브레이크 시스템의 플런저 장치에서 재충전 과정 시작 시점의 결정 방법 및 플런저 장치를 구비한 전자 슬립 제어식 파워 브레이크 시스템
US20060017322A1 (en) Vehicular brake control device

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20100927

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA RS

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20170901